use crate::prelude::TagKind;
use rome_console::fmt::Formatter;
use rome_console::markup;
use rome_diagnostics::{category, Category, Diagnostic, DiagnosticTags, Location, Severity};
use rome_rowan::{SyntaxError, TextRange};
use std::error::Error;

#[derive(Debug, PartialEq, Eq, Copy, Clone)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
/// Series of errors encountered during formatting
pub enum FormatError {
    /// In case a node can't be formatted because it either misses a require child element or
    /// a child is present that should not (e.g. a trailing comma after a rest element).
    SyntaxError,
    /// In case range formatting failed because the provided range was larger
    /// than the formatted syntax tree
    RangeError { input: TextRange, tree: TextRange },

    /// In case printing the document failed because it has an invalid structure.
    InvalidDocument(InvalidDocumentError),

    /// Formatting failed because some content encountered a situation where a layout
    /// choice by an enclosing [crate::Format] resulted in a poor layout for a child [crate::Format].
    ///
    /// It's up to an enclosing [crate::Format] to handle the error and pick another layout.
    /// This error should not be raised if there's no outer [crate::Format] handling the poor layout error,
    /// avoiding that formatting of the whole document fails.
    PoorLayout,
}

impl std::fmt::Display for FormatError {
    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            FormatError::SyntaxError => fmt.write_str("syntax error"),
            FormatError::RangeError { input, tree } => std::write!(
                fmt,
                "formatting range {input:?} is larger than syntax tree {tree:?}"
            ),
            FormatError::InvalidDocument(error) => std::write!(fmt, "Invalid document: {error}\n\n This is an internal Rome error. Please report if necessary."),
            FormatError::PoorLayout => {
                std::write!(fmt, "Poor layout: The formatter wasn't able to pick a good layout for your document. This is an internal Rome error. Please report if necessary.")
            }
        }
    }
}

impl Error for FormatError {}

impl From<SyntaxError> for FormatError {
    fn from(error: SyntaxError) -> Self {
        FormatError::from(&error)
    }
}

impl From<&SyntaxError> for FormatError {
    fn from(syntax_error: &SyntaxError) -> Self {
        match syntax_error {
            SyntaxError::MissingRequiredChild => FormatError::SyntaxError,
        }
    }
}

impl From<PrintError> for FormatError {
    fn from(error: PrintError) -> Self {
        FormatError::from(&error)
    }
}

impl From<&PrintError> for FormatError {
    fn from(error: &PrintError) -> Self {
        match error {
            PrintError::InvalidDocument(reason) => FormatError::InvalidDocument(*reason),
        }
    }
}

impl Diagnostic for FormatError {
    fn location(&self) -> Location<'_> {
        Location::builder().build()
    }

    fn severity(&self) -> Severity {
        Severity::Error
    }

    fn tags(&self) -> DiagnosticTags {
        match self {
            FormatError::SyntaxError => DiagnosticTags::empty(),
            FormatError::RangeError { .. } => DiagnosticTags::empty(),
            FormatError::InvalidDocument(_) => DiagnosticTags::INTERNAL,
            FormatError::PoorLayout => DiagnosticTags::INTERNAL,
        }
    }

    fn description(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        std::fmt::Display::fmt(self, fmt)
    }

    fn category(&self) -> Option<&'static Category> {
        Some(category!("format"))
    }

    fn message(
        &self,
        fmt: &mut rome_diagnostics::console::fmt::Formatter<'_>,
    ) -> std::io::Result<()> {
        match self {
            FormatError::SyntaxError => fmt.write_str("Syntax error."),
            FormatError::RangeError { input, tree } => std::write!(
                fmt,
                "Formatting range {input:?} is larger than syntax tree {tree:?}"
            ),
            FormatError::InvalidDocument(error) => std::write!(fmt, "Invalid document: {error}"),
            FormatError::PoorLayout => {
                std::write!(fmt, "Poor layout: The formatter wasn't able to pick a good layout for your document.")
            }
        }
    }
}

#[derive(Debug, Copy, Clone, Eq, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub enum InvalidDocumentError {
    /// Mismatching start/end kinds
    ///
    /// ```plain
    /// StartIndent
    /// ...
    /// EndGroup
    /// ```
    StartEndTagMismatch {
        start_kind: TagKind,
        end_kind: TagKind,
    },

    /// End tag without a corresponding start tag.
    ///
    /// ```plain
    /// Text
    /// EndGroup
    /// ```
    StartTagMissing { kind: TagKind },

    /// Expected a specific start tag but instead is:
    /// * at the end of the document
    /// * at another start tag
    /// * at an end tag
    ExpectedStart {
        expected_start: TagKind,
        actual: ActualStart,
    },
}

#[derive(Debug, Copy, Clone, Eq, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub enum ActualStart {
    /// The actual element is not a tag.
    Content,

    /// The actual element was a start tag of another kind.
    Start(TagKind),

    /// The actual element is an end tag instead of a start tag.
    End(TagKind),

    /// Reached the end of the document
    EndOfDocument,
}

impl std::fmt::Display for InvalidDocumentError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            InvalidDocumentError::StartEndTagMismatch {
                start_kind,
                end_kind,
            } => {
                std::write!(
                    f,
                    "Expected end tag of kind {start_kind:?} but found {end_kind:?}."
                )
            }
            InvalidDocumentError::StartTagMissing { kind } => {
                std::write!(f, "End tag of kind {kind:?} without matching start tag.")
            }
            InvalidDocumentError::ExpectedStart {
                expected_start,
                actual,
            } => {
                match actual {
                    ActualStart::EndOfDocument => {
                        std::write!(f, "Expected start tag of kind {expected_start:?} but at the end of document.")
                    }
                    ActualStart::Start(start) => {
                        std::write!(f, "Expected start tag of kind {expected_start:?} but found start tag of kind {start:?}.")
                    }
                    ActualStart::End(end) => {
                        std::write!(f, "Expected start tag of kind {expected_start:?} but found end tag of kind {end:?}.")
                    }
                    ActualStart::Content => {
                        std::write!(f, "Expected start tag of kind {expected_start:?} but found non-tag element.")
                    }
                }
            }
        }
    }
}

#[derive(Debug, Clone, Eq, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub enum PrintError {
    InvalidDocument(InvalidDocumentError),
}

impl Error for PrintError {}

impl std::fmt::Display for PrintError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            PrintError::InvalidDocument(inner) => {
                std::write!(f, "Invalid document: {inner}")
            }
        }
    }
}

impl Diagnostic for PrintError {
    fn category(&self) -> Option<&'static Category> {
        Some(category!("format"))
    }

    fn severity(&self) -> Severity {
        Severity::Error
    }

    fn message(&self, fmt: &mut Formatter<'_>) -> std::io::Result<()> {
        match self {
            PrintError::InvalidDocument(inner) => {
                let inner = format!("{}", inner);
                fmt.write_markup(markup! {
                    "Invalid document: "{{inner}}
                })
            }
        }
    }
}

#[cfg(test)]
mod test {
    use crate::diagnostics::{ActualStart, InvalidDocumentError};
    use crate::prelude::{FormatError, TagKind};
    use rome_diagnostics::{print_diagnostic_to_string, DiagnosticExt, Error};
    use rome_js_syntax::TextRange;

    fn snap_diagnostic(test_name: &str, diagnostic: Error) {
        let content = print_diagnostic_to_string(&diagnostic);

        insta::with_settings!({
            prepend_module_to_snapshot => false,
        }, {
            insta::assert_snapshot!(test_name, content);

        });
    }

    #[test]
    fn formatter_syntax_error() {
        snap_diagnostic(
            "formatter_syntax_error",
            FormatError::SyntaxError.with_file_path("example.js"),
        )
    }

    #[test]
    fn poor_layout() {
        snap_diagnostic(
            "poor_layout",
            FormatError::PoorLayout.with_file_path("example.js"),
        )
    }

    #[test]
    fn invalid_document() {
        snap_diagnostic(
            "invalid_document",
            FormatError::InvalidDocument(InvalidDocumentError::ExpectedStart {
                expected_start: TagKind::Align,
                actual: ActualStart::Start(TagKind::ConditionalContent),
            })
            .with_file_path("example.js"),
        )
    }

    #[test]
    fn range_error() {
        snap_diagnostic(
            "range_error",
            FormatError::RangeError {
                input: TextRange::new(7.into(), 10.into()),
                tree: TextRange::new(0.into(), 5.into()),
            }
            .with_file_path("example.js"),
        )
    }
}
